It was Sarnia’s habit to cross the road by the entrance to Chancery Lane, where the sweeper was Gimpy Jimmy. He was a tall thin white-haired man who had left a leg in Spain, fighting under the Duke’s command. He would never accept a coin from her, and she had ceased to urge it on him. He was puzzled, she knew, by the fact that, although a lady in appearance, she went to work. He himself was not in need of money. The position was a good one, and he had lived frugally and saved over the years.

Hilary Ford on the genesis of Sarnia: I envisaged a woman of the late nineteenth century marrying into this milieu, finding it unendurable and fleeing back with her child to the more ordinary hazards of...